Failure Analysis of Crankshaft in Diesel Engine Vehicle Using Numerical Method

In this study, there has been a failure of the crankshaft on a pick up vehicle using a diesel engine. After 3 months of use, the crankshaft broke on the crank arm. The purpose of this study was to determine the cause of crankshaft failure in a diesel engine pick up numerically. The crankshaft is modeled by using CAD to locate the initial defects in the crank web, then applying the finite element method to obtain the value and distribution of stresses that occur in the crankshaft and around the location of the initial defects. The results of the stress values obtained are then applied to calculate the stress intensity factor (KI) which will be compared with the fracture toughness value (KIC). From the simulation results and the calculation of the stress intensity factor (KI), it can be observed that there is a concentration of stress in the area of the initial defect. The amount of stress that occurs at the input in the value of the stress intensity factor is 91.827 MPa √m, while the fracture toughness of the material is 32.8934 MPa √m. The ratio of KI >  KIC at the crack tip causes crack propagation starting at the initial defect. Based on the results obtained, crack propagation due to loading and the concentration value at the crack tip area is the cause of failure of the crankshaft.